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Commit 363438ed authored by Michael Chan's avatar Michael Chan Committed by Greg Kroah-Hartman
Browse files

bnxt_en: Fix TX timeout when TX ring size is set to the smallest 



[ Upstream commit 5bed8b0704c9ecccc8f4a2c377d7c8e21090a82e ]

The smallest TX ring size we support must fit a TX SKB with MAX_SKB_FRAGS
+ 1.  Because the first TX BD for a packet is always a long TX BD, we
need an extra TX BD to fit this packet.  Define BNXT_MIN_TX_DESC_CNT with
this value to make this more clear.  The current code uses a minimum
that is off by 1.  Fix it using this constant.

The tx_wake_thresh to determine when to wake up the TX queue is half the
ring size but we must have at least BNXT_MIN_TX_DESC_CNT for the next
packet which may have maximum fragments.  So the comparison of the
available TX BDs with tx_wake_thresh should be >= instead of > in the
current code.  Otherwise, at the smallest ring size, we will never wake
up the TX queue and will cause TX timeout.

Fixes: c0c050c5 ("bnxt_en: New Broadcom ethernet driver.")
Reviewed-by: default avatarPavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: default avatarMichael Chan <michael.chan@broadocm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 4c4c3052

drivers/net/ethernet/broadcom/bnxt/bnxt.c

+4 −4
Original line number Diff line number Diff line
@@ -372,7 +372,7 @@ static bool bnxt_txr_netif_try_stop_queue(struct bnxt *bp, 
	 * netif_tx_queue_stopped().

	 */

	smp_mb();

	if (bnxt_tx_avail(bp, txr) > bp->tx_wake_thresh) {

	if (bnxt_tx_avail(bp, txr) >= bp->tx_wake_thresh) {

		netif_tx_wake_queue(txq);

		return false;

	}
@@ -701,7 +701,7 @@ static void bnxt_tx_int(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts) 
	smp_mb();



	if (unlikely(netif_tx_queue_stopped(txq)) &&

	    bnxt_tx_avail(bp, txr) > bp->tx_wake_thresh &&

	    bnxt_tx_avail(bp, txr) >= bp->tx_wake_thresh &&

	    READ_ONCE(txr->dev_state) != BNXT_DEV_STATE_CLOSING)

		netif_tx_wake_queue(txq);

}
@@ -2206,7 +2206,7 @@ static int __bnxt_poll_work(struct bnxt *bp, struct bnxt_cp_ring_info *cpr, 
		if (TX_CMP_TYPE(txcmp) == CMP_TYPE_TX_L2_CMP) {

			tx_pkts++;

			/* return full budget so NAPI will complete. */

			if (unlikely(tx_pkts > bp->tx_wake_thresh)) {

			if (unlikely(tx_pkts >= bp->tx_wake_thresh)) {

				rx_pkts = budget;

				raw_cons = NEXT_RAW_CMP(raw_cons);

				if (budget)
@@ -3329,7 +3329,7 @@ static int bnxt_init_tx_rings(struct bnxt *bp) 
	u16 i;



	bp->tx_wake_thresh = max_t(int, bp->tx_ring_size / 2,

				   MAX_SKB_FRAGS + 1);

				   BNXT_MIN_TX_DESC_CNT);



	for (i = 0; i < bp->tx_nr_rings; i++) {

		struct bnxt_tx_ring_info *txr = &bp->tx_ring[i];

drivers/net/ethernet/broadcom/bnxt/bnxt.h

+5 −0
Original line number Diff line number Diff line
@@ -601,6 +601,11 @@ struct nqe_cn { 
#define BNXT_MAX_RX_JUM_DESC_CNT	(RX_DESC_CNT * MAX_RX_AGG_PAGES - 1)

#define BNXT_MAX_TX_DESC_CNT		(TX_DESC_CNT * MAX_TX_PAGES - 1)



/* Minimum TX BDs for a TX packet with MAX_SKB_FRAGS + 1.  We need one extra

 * BD because the first TX BD is always a long BD.

 */

#define BNXT_MIN_TX_DESC_CNT		(MAX_SKB_FRAGS + 2)



#define RX_RING(x)	(((x) & ~(RX_DESC_CNT - 1)) >> (BNXT_PAGE_SHIFT - 4))

#define RX_IDX(x)	((x) & (RX_DESC_CNT - 1))

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c

+1 −1
Original line number Diff line number Diff line
@@ -744,7 +744,7 @@ static int bnxt_set_ringparam(struct net_device *dev, 


	if ((ering->rx_pending > BNXT_MAX_RX_DESC_CNT) ||

	    (ering->tx_pending > BNXT_MAX_TX_DESC_CNT) ||

	    (ering->tx_pending <= MAX_SKB_FRAGS))

	    (ering->tx_pending < BNXT_MIN_TX_DESC_CNT))

		return -EINVAL;



	if (netif_running(dev))